It’s going to take more than a year before your raspberry plants will start to produce fruit. But that shouldn’t matter. Once they are growing you will have the promise of delicious, sweet berries right from your own raspberry patch, and they will continue producing fruit year after year.
The question is when to plant raspberries in your home garden? It depends on whether you are starting with seeds, seedlings, or an established raspberry cane. If transplanting seedlings, plant in late winter in the south or early spring in the north of Canada or the U.S. Sow seeds in mid-winter.
Planting Raspberry Bushes in Different Climates
Raspberries generally grow best in cooler climates, but there are many raspberry varieties that are suited to different planting zones. So, wherever you live, if you are planning to grow raspberries choose varieties that will survive, if not thrive, in your area.
Plant-growing guides, seed packets, and labels on commercially-raised raspberry bushes and canes often state which zones are best for the plant.
North American Planting Zones
The United States Department of Agriculture (USDA) created a plant hardiness zone map that has become the standard for gardeners to use when determining which plants will thrive where. Last updated in 2012, the map is based on each area’s annual minimum winter temperature.
There are a total of 13 planting zones, each 10°F colder or warmer than the next. Each zone is further divided into two zones, a and b, each 5°F apart.
The Government of Canada has also created a plant hardiness zone map. This one is divided into 10 zones (also with a and b in all but the warmest zone), ranging from 0a to 9a.
Both maps are online and interactive and very useful tools for ascertaining what will grow in your area.
International Climate Classifications
In addition to planting zones, there are broader climate groups that are based on rainfall and temperature patterns. The Koöpen climate classification system is not limited to North America and it is the most widely known system used globally.
There are five main climate groups:
Each of these is divided into subcategories that are also based on rainfall and temperature.
So, if you know the rainfall needs and optimum temperature required to grow raspberries, these classifications are also invaluable.
Best Climate Conditions for Growing Raspberries
Raspberries are a cool-weather plant. Most varieties do best in northern regions where the summers are cool and winters relatively mild.
Home gardeners who live in the USDA Zones 3-10 can grow raspberries successfully if they choose suitable raspberry varieties. But most cultivars are grown in Zones 4-8.
There are a few raspberry varieties, including Oregon 1030 and Bababerry, that have been cultivated to withstand a hot, sunny climate. But most thrive in moist, cool conditions.
Raspberries don’t need a lot of water, but they don’t do well if there isn’t enough moisture. The most critical time is from when they bloom until the berries are ready to harvest.
If rainfall is inadequate, you’ll have to irrigate.
A 2014 Danish study that focuses on the effects of temperature on raspberry physiology discusses the protected cultivation of raspberries in growing tunnels and greenhouses. This not only makes it possible to grow raspberries throughout the year but also in areas that offer less than perfect growing conditions – hot or cold.
Tropical climates are hot (an average of 64.4°F/18°C or higher) with significant rainfall. So, generally, it’s too hot and wet unless you can plant a variety that has been cultivated to withstand these conditions.
Gardens in USDA Zones 9-11 are considered tropical.
There are hot and cold semi-arid and desert climates, all of which have average temperatures that vary. If temperatures in your area are cool, you can try growing raspberries but will have to establish an irrigation plan that works.
You’ve probably got a 50:50 chance of success.
According to the Danish study mentioned above, most raspberry production takes place in cool temperate climate areas globally. This stands to reason since raspberries are believed to have originated in the cooler temperate regions of Turkey.
So, if you live in a cool temperate climate your raspberries have every chance of thriving.
Continental climates are very varied. There are 12 sub-categories! Be guided by the average temperature and rainfall in your area.
Generally, raspberries plants become dormant in the late fall when temperatures decrease. So, it seems obvious that a polar climate, which has temperatures below 50°F or 10°C even in the hottest month, is not the place where raspberries can be grown outdoors.
To grow raspberries in a polar climate, you’ll need shelter and induced warmth and light. Grow tunnels that don’t block UV light and grow lights are a possible solution.
Choosing Raspberry Seeds
While it is a lot easier to plant bare root raspberries or an established raspberry cane, seeds are available. Your choice will usually be in terms of color – red, black, yellow, white, and so on – or which planting zones they have been cultivated for.
Other than that, there are two types of raspberries, those that fruit in summer and those that bear fruit in the fall and then again the following summer. Instead of choosing one or the other, consider a mix of both types to increase your harvest period.
Just remember that you will need to plant your seeds so that the seedlings are ready to plant out once temperatures reach at least 60°F/16°C. This will usually be in early to mid-spring.
Also, you won’t get any berries off your plants until at least 16-18 months after you have planted.
How to Plant Raspberry Seeds
Whether you are growing raspberries from seed, planting dormant bare root plants, or established canes, you need to choose a suitable site that gets full sun during the growing season. In hot climates, make sure they will get some cooling afternoon shade.
You must also prepare the soil prior to planting.
Prepare the Soil Prior to Planting Raspberries
Whether you are growing raspberries in a conventional or raised bed, or a pot, they grow best in rich, well-drained soil. Add organic matter and compost to the soil and dig it in thoroughly.
The National Gardening Association recommends that we grow raspberries in slightly acidic soil that has a pH of 5.5-6.8.
Planting Rosemary Seeds
A good way to plant rosemary seeds is in peat in seed trays. Plant about an inch deep and cover with a little sandy soil.
Keep the trays in a light but not bright, cool environment.
When the seedlings emerge, you can thin them out. In the meantime, keep the seed trays moist by spraying water over them.
You can transplant them into a large pot or garden bed when the seedlings have grown at least an inch (2.5 cm) high. You can also transfer the peat pots outdoors before they are ready as long as the temperature is at least 60°F/16°C.
When you plant bare root raspberries be sure to keep them moist until you are ready to plant them. Do this by covering with damp soil or peat moss, and keep it moist.
When planting canes, cut each one back to about 8 inches (20 cm) so that the roots will establish themselves. Cut black raspberry canes back to ground level to prevent anthracnose disease.
When to Plant Raspberry Seeds
Plant your raspberry seeds so that they will be sufficiently developed and ready for planting in late winter or early spring, depending on where you live.
They will take 4-6 weeks to germinate and another 4 weeks or so to grow large and strong enough to be planted outdoors.
This means you should plant raspberry seeds about two months before you are going to plant them outside.
How to Water Raspberries
The moisture level of the soil you grow raspberries in needs to be consistent through the growing season. While the fruit is developing, they need 1-1.5 inches (2.5-3.8 cm) of water, either from the rain or irrigation.
The root system of raspberries settles in the top 2 feet (60 cm) of soil. So, it is best to water regularly rather than giving a deep soaking less frequently.
If the weather is dry, soak the ground to a depth of 10-12 inches (25-30 cm) every week. To avoid the risk of disease, try not to get the foliage and fruit wet.
Drip irrigation and soaker hoses are ideal for watering raspberries.
How to Grow Raspberries
We have discussed planting and watering raspberries, now let’s look at a few other important issues.
Support for Raspberries
Raspberries can grow to heights of 3-5 feet tall. So, whichever type of raspberry plants you decide to grow, they will need support to prevent wind damage as the canes grow.
Most purple and black raspberries can be individually staked, otherwise, a simple trellis will do the trick.
How to Prune Raspberries
You will only do this once you have finished harvesting your delicious berries. And all you do is to cut the canes back to the ground – but only cut the canes that pave produced berries.
The old fruitful stems will be brown and the younger canes growing next to them will be green.
Managing Pests and Diseases
Raspberries tend to be healthy and the plants aren’t bothered by insects or diseases as much as most other fruits. In reality, birds are likely to be the biggest pest if you aren’t willing to share your fruit with them!
The cane borer, which lays its eggs near the top of newly grown canes, can be a problem. Try to pinpoint the borer and cut the canes to remove them.
The National Gardening Association offers simple but invaluable advice. Practice careful garden sanitation and get rid of any wild raspberry plants growing nearby (within 300 feet/91 m).
Fungal diseases present the greatest threat, including anthracnose disease, which causes dark lesions on leaves, and verticillium wilt. The latter is the real baddie.
THE RISK OF VERTICILLIUM WILT
Verticillium wilt is a soil-borne fungal disease that can kill the fruiting raspberry cane or even the whole plant.
Rule number one: Don’t plant your raspberries together with peppers, eggplants, potatoes, tomatoes, or other nightshade plants that might harbor verticillium wilt.
A factsheet released by The Ohio State University College of Food, Agricultural, and Environmental Sciences, Verticillium Wilt of Raspberries, warns that this is one of the most serious diseases that besets raspberry bushes and canes.
It’s a cool-weather disease that is most severe in poorly drained soil after a spring season that has been cold and wet. It often coincides with water stress that is caused by hot, dry weather in mid-summer.
According to the factsheet, verticillium wilt is more severe in black raspberries than red raspberries. It also affects blackberries, but not as severely. The factsheet advises home gardeners and commercial growers to only grow nursery plants that are known to be free of verticillium wilt.
So, don’t be tempted to transplant from a neighbor’s yard. If you start with good disease-free stock, your raspberry canes may live for at least 15 years.
How Long Do Raspberries Take to Grow?
Raspberry seeds take 4-6 weeks to germinate. Then you need to wait another month for them to establish themselves before you transplant them.
But it’s going to take a long time for them to produce fruit. Canes that produce raspberries only bear fruit from their second season.
All in all, it can take as long as 18 months for raspberries to grow and produce berries that you can harvest. But, raspberries will continue to grow, sometimes for as long as 15 or more years.
Raspberries are one of the easiest fruits to grow. They are resistant to most diseases and are attacked by surprisingly few pests.
Our plant guide has been designed to make growing raspberries simple, easy, and amazingly rewarding. We have aimed to show you that wherever you live you can grow these delicious berries in your home garden.
What’s stopping you?